Process of producing silicon carbid.



F. J. TONE. PROCESS OF PRODUGING SILICON UARBID.

APPLICATION FILED APR.1,1908.

' Patented 0ct.19,'19 09.

UNITED sTArnsPAT NT oruucn.

FRANK J. TONE, 0F NIAGARA FALLS, NEW-YORK, AS SIGNOR TO THE CARBORUNDUM COMPANY, OF NIAGARA FALLS, NEW YORK, A CORPORATION OF PENNSYLVANIA.

PROCESS OF PRODUCING SILICON CARBID.

Specification of Letters Patent.

Application filed Aprill, 1908. Serial No. 424,600.

To all whom it may concern.

Be it known that L'FRANK J. TONE, of Niagara Falls, Niagara county, New York, have invented a new and useful Improvement in Processes of ProducingSilicon Carbid, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which the figure is a section of an electric furnace in which I may carry out my process.

My invention relates to the production of silicon carbid, and is designed to provide an improved economical method for the production of the same in grades which are especially adapted for certain purposes in the arts.

As commonly carried out, the manufacture of silicon carbid consists in embedding a resistance conductor in a charge mixture of silica and carbon, passing current through the conductor and generating heat suflicient to reduce the silica and convert it into silicon carbid, the heat being generated entirely on the incandescence principle. I have discovered that silicon carbid can be elliciently produced in the arc furnace and that this method has great advantages when it is desired to use certain grades of crude materials or to obtain silicon carbidof certain specific properties. 1

Referring to the drawings, 2 is an electric furnace built of refractory material, 3, 3 are carbon electrodes depending vertically'into the furnace and surrounded by the mixing charge 4. After the arc is started in the usual manner, the mixing charge 4 is gradu ally added until it entirely surrounds the electrodes and covers the arc zone. When sufliciently heated that part ofthe mixing charge within. the arc zone and under the electrodes is converted into silicon carbid, and by-raising the electrodes from time to time as may be necessary or desired to secure the roper regulation of the current, the finishe product builds up to any desired height. Fresh mixture is added around the electrodes from time to time as the charge under treatment carbid.

If it is desired to run'the furnace continuously the finished product may be withdrawn from the column which has built up is converted into silicon under the electrodes at the farthest point from the arc zone continuously or intermittently, without shutting down the furnace o1 disturbing the mass in the Vicinity of the mixture contains white stuff (which term 65 furnace which has already is applied to theggartially converted mixture of a silicon carbi been used in the process), the area of the reaction zone is thereby increased and rendered more efficient. It has been found that the silicon carbid formed by this process is of a dense compact variety, and has great toughness. These qualities make it Very valuable and efiicient, for certain abrasive purposes, as well as for other uses.

My process is not confined to use in the furnace shown, but may be used in any type of arc furnace withoutdeparting from my invention, since What I claim 1s:

1. The process of producing silicon car Patented Oct. 19, 1909.,

bid, consisting in subyecting a mixture of silicious and carbonaceous material to the heat of an electric arc-"sulficient to produce' silicon carbid and moving the arc zone from the formed silicon carbid in the direction of the unreduced mixture. I

2. The process of producing silicon carbid, consisting in introducing a charge of silicious and carbonaceous material into a furnace, subjecting said mixture to the heat of' an electric arc, thereby causing a reaction of the mixture to form silicon carbid and moving the arc zone from the formed silicon carbid in the direction of the uureduced mixture.

3. .The process of producing silicon car bid, which consistsin'supplying acharge of silicious and carbonaceous material, maintaining'within the charge an electric arc of suflicient heating capacity to produce silicon carbid and moving the arc zone from the formed silicon carbid in the directionof the unreduced mixture.

4. The process of producingsilicon carbid, which consists in supplying a charge of silicious and carbonaceous material, main-' taining within the charge an electric arc of suflicient heating capacity to produce SlllCOIl carbid, allowing the silicon carbid to build up under the electrodes as it is formed, and supplying fresh charges as required.

5. The process of producing silicon carbid, which consists in supplying a charge of silicious and carbonaceous material, main taining within the charge an electric arc of sufficient heating capacity to produce silicon carbid, allowing a column of silicon carbid to build up under the elect! odes as it is formed, Withdrawing portions of silicon carbid from the end of the column farthest from the arc zone from time to time and supplying fresh charge as required.

6. The process of producing silicon carbid, consisting in sub ecting a mixturelfiofil silicious and carbonaceous material to the heat of an electric arc sufliient to produce silicon carbid, said mixture containing partially reduced charge formed in the production of silicon carbid and known as white stufi and moving the arc zone from the formed silicon carbid in the direction of the unreduced mixture.

7. The process of producing silicon carbid which consists, in applying a charge of silicious and carbonaceous material, maintaining Within the charge an electric arc of sutficient heating capacity to produce silicon carbid, and raisingthe arc-producing electrodes from time to time to secure the proper regulation of the current and to allow the finished product to build up underneath the electrodes as it is formed.

In testimony whereof, I have hereunto set 

